A football is kicked into the air with a velocity of 32m/s at an angle of 25º. At the very top of the ball's path, its vertical velocity is

At the "very top" of the ball's path, there's a tiny instant when the ball

is changing from "going up" to "going down". At that exact tiny instant,

its vertical speed is zero.

You can't go from "rising" to "falling" without passing through "zero vertical

speed", at least for an instant. It makes sense, and it feels right, but that's

not good enough in real Math. There's a big, serious, important formal law

in Calculus that says it. I think Newton may have been the one to prove it,

and it's named for him.

By the way ... it doesn't matter what the football's launch angle was,

or how hard it was kicked, or what its speed was off the punter's toe,

or how high it went, or what color it is, or who it belongs to, or even

whether it's full to the correct regulation air pressure. Its vertical speed

is still zero at the very top of its path, as it's turning around and starting

to fall.